The Domain Name System (DNS) is the part of the Internet infrastructure that translates human-readable domain names into the Internet Protocol (IP) addresses needed to establish communications over the Internet. The DNS comprises DNS servers that run software permitting them to query DNS databases. The DNS databases contain records associating particular domain names with specific IP addresses. This allows users to refer to web sites and other resources using easier to remember domain names such as “example.com” rather than numeric IP addresses such as “123.4.56.78”.
Each domain name is made up of a series of character strings (labels) separated by dots. The right-most label in a domain name is known as the “top-level domain” (TLD). Examples of well-known TLDs are “.com”; “.net”; and “.org.”. Each TLD supports second-level domains that are located immediately to the left of the TLD (e.g., “example” in “www.example.com”). Each second-level domain can be followed by a third-level domain located immediately to the left of the second-level domain (e.g., “www” in “www.example.com”). There can be additional domain levels as well. For example, a domain with additional domain levels could be “www.photos.example.com”.
A single IP address associated with a particular machine can support numerous domain names. That is, different domain names may resolve to the same server, and the server can determine what content to provide based on the requested domain name or additional non-domain information. Additional non-domain information may be included in a Uniform Resource Identifier (URI) structure that includes the domain name. For example, a “path” part is a sequence of segments separated by a forward slash (“/”). This information may be included immediately to the right of the domain name, such as “blog” in “www.example.com/blog”, and may be used by a server or other receiving computer to identify and deliver specific content or run particular code. This information is often included in web page hyperlinks that navigate a user to another section of the web page or to a different web page.
Related domain names and content may be organized in an hierarchical manner, such as “www.example.com”; “www.blog.example.com”; “www.example.com/blog”; or “blog.example.com”. Such related domain names need not share the same IP address. In this regard, part of the domain name may signify a particular server. For example “mail.example.com” and “www.example.com” may resolve to different servers with different functions despite the same second-level domain.
The Internet Corporation for Assigned Names and Numbers (ICANN) is responsible for managing the assignment of domain names and IP addresses. ICANN delegates the responsibility for operating the TLDs (including maintaining a registry of the second-level domains within the TLDs) to organizations known as a domain name registries. Registries are primarily responsible for converting domain names to IP addresses (“resolving”) using DNS servers.
The actual registration of domain names is performed by companies referred to as domain name registrars. Registrars register domain names with the registries. For example, an end user (i.e., “registrant”) goes through a registrar to register a domain name with a particular registry.
The registration of domain names is important because a domain name is the identifier by which an individual or entity (e.g., a company, a governmental agency, an educational institution, etc.) can be found on the Internet. Individuals and entities would like to have domain names that are easily remembered. For example, a word that is commonly associated with a particular person or company is generally preferred as a domain name because it is easier to remember. The number of words that are not yet registered as domain names, however, continues to decrease as the number of registered domain names increases. Most common words are already registered as domain names making it increasingly difficult to identify available words (i.e., unregistered domain names) that would be easy to remember and would serve as good domain names. Thus, there is a need in the art for methods and apparatus for characterizing unregistered domain names.